/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ /* vim: set ts=8 sts=2 et sw=2 tw=80: */ /* This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ // IWYU pragma: private, include "nsISupports.h" #ifndef nsISupportsImpl_h__ #define nsISupportsImpl_h__ #include "nscore.h" #include "nsISupportsBase.h" #include "nsISupportsUtils.h" #if !defined(XPCOM_GLUE_AVOID_NSPR) #include "prthread.h" /* needed for thread-safety checks */ #endif // !XPCOM_GLUE_AVOID_NSPR #include "nsDebug.h" #include "nsXPCOM.h" #ifndef XPCOM_GLUE #include "mozilla/Atomics.h" #endif #include "mozilla/Attributes.h" #include "mozilla/Assertions.h" #include "mozilla/Compiler.h" #include "mozilla/Likely.h" #include "mozilla/MacroArgs.h" #include "mozilla/MacroForEach.h" #include "mozilla/TypeTraits.h" namespace mozilla { template struct HasDangerousPublicDestructor { static const bool value = false; }; } #if defined(__clang__) // bug 1028428 shows that at least in FreeBSD 10.0 with Clang 3.4 and libc++ 3.4, // std::is_destructible is buggy in that it returns false when it should return true // on ipc::SharedMemory. On the other hand, all Clang versions currently in use // seem to handle the fallback just fine. # define MOZ_CAN_USE_IS_DESTRUCTIBLE_FALLBACK #elif defined(__GNUC__) // GCC 4.7 is has buggy std::is_destructible # if MOZ_USING_LIBSTDCXX && MOZ_GCC_VERSION_AT_LEAST(4, 8, 0) # define MOZ_HAVE_STD_IS_DESTRUCTIBLE // Some GCC versions have an ICE when using destructors in decltype(). // Works on GCC 4.8 at least. # elif MOZ_GCC_VERSION_AT_LEAST(4, 8, 0) # define MOZ_CAN_USE_IS_DESTRUCTIBLE_FALLBACK # endif #endif #ifdef MOZ_HAVE_STD_IS_DESTRUCTIBLE # include # define MOZ_IS_DESTRUCTIBLE(X) (std::is_destructible::value) #elif defined MOZ_CAN_USE_IS_DESTRUCTIBLE_FALLBACK namespace mozilla { struct IsDestructibleFallbackImpl { template().~T())> static TrueType Test(int); template static FalseType Test(...); template struct Selector { typedef decltype(Test(0)) type; }; }; template struct IsDestructibleFallback : IsDestructibleFallbackImpl::Selector::type { }; } # define MOZ_IS_DESTRUCTIBLE(X) (mozilla::IsDestructibleFallback::value) #endif #ifdef MOZ_IS_DESTRUCTIBLE #define MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(X) \ static_assert(!MOZ_IS_DESTRUCTIBLE(X) || \ mozilla::HasDangerousPublicDestructor::value, \ "Reference-counted class " #X " should not have a public destructor. " \ "Try to make this class's destructor non-public. If that is really " \ "not possible, you can whitelist this class by providing a " \ "HasDangerousPublicDestructor specialization for it."); \ static_assert(!mozilla::HasDangerousPublicDestructor::value || \ MOZ_IS_DESTRUCTIBLE(X), \ "Class " #X " has no public destructor. That's good! So please " \ "remove the HasDangerousPublicDestructor specialization for it."); #else #define MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(X) #endif inline nsISupports* ToSupports(nsISupports* aSupports) { return aSupports; } inline nsISupports* ToCanonicalSupports(nsISupports* aSupports) { return nullptr; } //////////////////////////////////////////////////////////////////////////////// // Macros to help detect thread-safety: #if (defined(DEBUG) || (defined(NIGHTLY_BUILD) && !defined(MOZ_PROFILING))) && !defined(XPCOM_GLUE_AVOID_NSPR) class nsAutoOwningThread { public: nsAutoOwningThread() { mThread = PR_GetCurrentThread(); } void* GetThread() const { return mThread; } private: void* mThread; }; #define NS_DECL_OWNINGTHREAD nsAutoOwningThread _mOwningThread; #define NS_ASSERT_OWNINGTHREAD_AGGREGATE(agg, _class) \ NS_CheckThreadSafe(agg->_mOwningThread.GetThread(), #_class " not thread-safe") #define NS_ASSERT_OWNINGTHREAD(_class) NS_ASSERT_OWNINGTHREAD_AGGREGATE(this, _class) #else // !DEBUG && !(NIGHTLY_BUILD && !MOZ_PROFILING) #define NS_DECL_OWNINGTHREAD /* nothing */ #define NS_ASSERT_OWNINGTHREAD_AGGREGATE(agg, _class) ((void)0) #define NS_ASSERT_OWNINGTHREAD(_class) ((void)0) #endif // DEBUG || (NIGHTLY_BUILD && !MOZ_PROFILING) // Macros for reference-count and constructor logging #if defined(NS_BUILD_REFCNT_LOGGING) && !defined(MOZILLA_XPCOMRT_API) #define NS_LOG_ADDREF(_p, _rc, _type, _size) \ NS_LogAddRef((_p), (_rc), (_type), (uint32_t) (_size)) #define NS_LOG_RELEASE(_p, _rc, _type) \ NS_LogRelease((_p), (_rc), (_type)) #include "mozilla/TypeTraits.h" #define MOZ_ASSERT_CLASSNAME(_type) \ static_assert(mozilla::IsClass<_type>::value, \ "Token '" #_type "' is not a class type.") // Older versions of gcc can't instantiate local classes in templates. // GCC 4.7 doesn't have this problem. #if MOZ_IS_GCC # if !MOZ_GCC_VERSION_AT_LEAST(4, 7, 0) # undef MOZ_ASSERT_CLASSNAME # define MOZ_ASSERT_CLASSNAME(_type) # endif #endif // Note that the following constructor/destructor logging macros are redundant // for refcounted objects that log via the NS_LOG_ADDREF/NS_LOG_RELEASE macros. // Refcount logging is preferred. #define MOZ_COUNT_CTOR(_type) \ do { \ MOZ_ASSERT_CLASSNAME(_type); \ NS_LogCtor((void*)this, #_type, sizeof(*this)); \ } while (0) #define MOZ_COUNT_CTOR_INHERITED(_type, _base) \ do { \ MOZ_ASSERT_CLASSNAME(_type); \ MOZ_ASSERT_CLASSNAME(_base); \ NS_LogCtor((void*)this, #_type, sizeof(*this) - sizeof(_base)); \ } while (0) #define MOZ_LOG_CTOR(_ptr, _name, _size) \ do { \ NS_LogCtor((void*)_ptr, _name, _size); \ } while (0) #define MOZ_COUNT_DTOR(_type) \ do { \ MOZ_ASSERT_CLASSNAME(_type); \ NS_LogDtor((void*)this, #_type, sizeof(*this)); \ } while (0) #define MOZ_COUNT_DTOR_INHERITED(_type, _base) \ do { \ MOZ_ASSERT_CLASSNAME(_type); \ MOZ_ASSERT_CLASSNAME(_base); \ NS_LogDtor((void*)this, #_type, sizeof(*this) - sizeof(_base)); \ } while (0) #define MOZ_LOG_DTOR(_ptr, _name, _size) \ do { \ NS_LogDtor((void*)_ptr, _name, _size); \ } while (0) /* nsCOMPtr.h allows these macros to be defined by clients * These logging functions require dynamic_cast, so they don't * do anything useful if we don't have dynamic_cast. */ #define NSCAP_LOG_ASSIGNMENT(_c, _p) \ if (_p) \ NS_LogCOMPtrAddRef((_c),static_cast(_p)) #define NSCAP_LOG_RELEASE(_c, _p) \ if (_p) \ NS_LogCOMPtrRelease((_c), static_cast(_p)) #else /* !NS_BUILD_REFCNT_LOGGING */ #define NS_LOG_ADDREF(_p, _rc, _type, _size) #define NS_LOG_RELEASE(_p, _rc, _type) #define MOZ_COUNT_CTOR(_type) #define MOZ_COUNT_CTOR_INHERITED(_type, _base) #define MOZ_LOG_CTOR(_ptr, _name, _size) #define MOZ_COUNT_DTOR(_type) #define MOZ_COUNT_DTOR_INHERITED(_type, _base) #define MOZ_LOG_DTOR(_ptr, _name, _size) #endif /* NS_BUILD_REFCNT_LOGGING */ // Support for ISupports classes which interact with cycle collector. #define NS_NUMBER_OF_FLAGS_IN_REFCNT 2 #define NS_IN_PURPLE_BUFFER (1 << 0) #define NS_IS_PURPLE (1 << 1) #define NS_REFCOUNT_CHANGE (1 << NS_NUMBER_OF_FLAGS_IN_REFCNT) #define NS_REFCOUNT_VALUE(_val) (_val >> NS_NUMBER_OF_FLAGS_IN_REFCNT) class nsCycleCollectingAutoRefCnt { public: nsCycleCollectingAutoRefCnt() : mRefCntAndFlags(0) {} explicit nsCycleCollectingAutoRefCnt(uintptr_t aValue) : mRefCntAndFlags(aValue << NS_NUMBER_OF_FLAGS_IN_REFCNT) { } MOZ_ALWAYS_INLINE uintptr_t incr(nsISupports* aOwner) { return incr(aOwner, nullptr); } MOZ_ALWAYS_INLINE uintptr_t incr(void* aOwner, nsCycleCollectionParticipant* aCp) { mRefCntAndFlags += NS_REFCOUNT_CHANGE; mRefCntAndFlags &= ~NS_IS_PURPLE; // For incremental cycle collection, use the purple buffer to track objects // that have been AddRef'd. if (!IsInPurpleBuffer()) { mRefCntAndFlags |= NS_IN_PURPLE_BUFFER; // Refcount isn't zero, so Suspect won't delete anything. MOZ_ASSERT(get() > 0); NS_CycleCollectorSuspect3(aOwner, aCp, this, nullptr); } return NS_REFCOUNT_VALUE(mRefCntAndFlags); } MOZ_ALWAYS_INLINE void stabilizeForDeletion() { // Set refcnt to 1 and mark us to be in the purple buffer. // This way decr won't call suspect again. mRefCntAndFlags = NS_REFCOUNT_CHANGE | NS_IN_PURPLE_BUFFER; } MOZ_ALWAYS_INLINE uintptr_t decr(nsISupports* aOwner, bool* aShouldDelete = nullptr) { return decr(aOwner, nullptr, aShouldDelete); } MOZ_ALWAYS_INLINE uintptr_t decr(void* aOwner, nsCycleCollectionParticipant* aCp, bool* aShouldDelete = nullptr) { MOZ_ASSERT(get() > 0); if (!IsInPurpleBuffer()) { mRefCntAndFlags -= NS_REFCOUNT_CHANGE; mRefCntAndFlags |= (NS_IN_PURPLE_BUFFER | NS_IS_PURPLE); uintptr_t retval = NS_REFCOUNT_VALUE(mRefCntAndFlags); // Suspect may delete 'aOwner' and 'this'! NS_CycleCollectorSuspect3(aOwner, aCp, this, aShouldDelete); return retval; } mRefCntAndFlags -= NS_REFCOUNT_CHANGE; mRefCntAndFlags |= (NS_IN_PURPLE_BUFFER | NS_IS_PURPLE); return NS_REFCOUNT_VALUE(mRefCntAndFlags); } MOZ_ALWAYS_INLINE void RemovePurple() { MOZ_ASSERT(IsPurple(), "must be purple"); mRefCntAndFlags &= ~NS_IS_PURPLE; } MOZ_ALWAYS_INLINE void RemoveFromPurpleBuffer() { MOZ_ASSERT(IsInPurpleBuffer()); mRefCntAndFlags &= ~(NS_IS_PURPLE | NS_IN_PURPLE_BUFFER); } MOZ_ALWAYS_INLINE bool IsPurple() const { return !!(mRefCntAndFlags & NS_IS_PURPLE); } MOZ_ALWAYS_INLINE bool IsInPurpleBuffer() const { return !!(mRefCntAndFlags & NS_IN_PURPLE_BUFFER); } MOZ_ALWAYS_INLINE nsrefcnt get() const { return NS_REFCOUNT_VALUE(mRefCntAndFlags); } MOZ_ALWAYS_INLINE operator nsrefcnt() const { return get(); } private: uintptr_t mRefCntAndFlags; }; class nsAutoRefCnt { public: nsAutoRefCnt() : mValue(0) {} explicit nsAutoRefCnt(nsrefcnt aValue) : mValue(aValue) {} // only support prefix increment/decrement nsrefcnt operator++() { return ++mValue; } nsrefcnt operator--() { return --mValue; } nsrefcnt operator=(nsrefcnt aValue) { return (mValue = aValue); } operator nsrefcnt() const { return mValue; } nsrefcnt get() const { return mValue; } static const bool isThreadSafe = false; private: nsrefcnt operator++(int) = delete; nsrefcnt operator--(int) = delete; nsrefcnt mValue; }; #ifndef XPCOM_GLUE namespace mozilla { class ThreadSafeAutoRefCnt { public: ThreadSafeAutoRefCnt() : mValue(0) {} explicit ThreadSafeAutoRefCnt(nsrefcnt aValue) : mValue(aValue) {} // only support prefix increment/decrement MOZ_ALWAYS_INLINE nsrefcnt operator++() { return ++mValue; } MOZ_ALWAYS_INLINE nsrefcnt operator--() { return --mValue; } MOZ_ALWAYS_INLINE nsrefcnt operator=(nsrefcnt aValue) { return (mValue = aValue); } MOZ_ALWAYS_INLINE operator nsrefcnt() const { return mValue; } MOZ_ALWAYS_INLINE nsrefcnt get() const { return mValue; } static const bool isThreadSafe = true; private: nsrefcnt operator++(int) = delete; nsrefcnt operator--(int) = delete; // In theory, RelaseAcquire consistency (but no weaker) is sufficient for // the counter. Making it weaker could speed up builds on ARM (but not x86), // but could break pre-existing code that assumes sequential consistency. Atomic mValue; }; } #endif /////////////////////////////////////////////////////////////////////////////// /** * Declare the reference count variable and the implementations of the * AddRef and QueryInterface methods. */ #define NS_DECL_ISUPPORTS \ public: \ NS_IMETHOD QueryInterface(REFNSIID aIID, \ void** aInstancePtr) override; \ NS_IMETHOD_(MozExternalRefCountType) AddRef(void) override; \ NS_IMETHOD_(MozExternalRefCountType) Release(void) override; \ protected: \ nsAutoRefCnt mRefCnt; \ NS_DECL_OWNINGTHREAD \ public: #define NS_DECL_THREADSAFE_ISUPPORTS \ public: \ NS_IMETHOD QueryInterface(REFNSIID aIID, \ void** aInstancePtr) override; \ NS_IMETHOD_(MozExternalRefCountType) AddRef(void) override; \ NS_IMETHOD_(MozExternalRefCountType) Release(void) override; \ protected: \ ::mozilla::ThreadSafeAutoRefCnt mRefCnt; \ NS_DECL_OWNINGTHREAD \ public: #define NS_DECL_CYCLE_COLLECTING_ISUPPORTS \ public: \ NS_IMETHOD QueryInterface(REFNSIID aIID, \ void** aInstancePtr) override; \ NS_IMETHOD_(MozExternalRefCountType) AddRef(void) override; \ NS_IMETHOD_(MozExternalRefCountType) Release(void) override; \ NS_IMETHOD_(void) DeleteCycleCollectable(void); \ protected: \ nsCycleCollectingAutoRefCnt mRefCnt; \ NS_DECL_OWNINGTHREAD \ public: /////////////////////////////////////////////////////////////////////////////// /* * Implementation of AddRef and Release for non-nsISupports (ie "native") * cycle-collected classes that use the purple buffer to avoid leaks. */ #define NS_IMPL_CC_NATIVE_ADDREF_BODY(_class) \ MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(_class) \ MOZ_ASSERT(int32_t(mRefCnt) >= 0, "illegal refcnt"); \ NS_ASSERT_OWNINGTHREAD(_class); \ nsrefcnt count = \ mRefCnt.incr(static_cast(this), \ _class::NS_CYCLE_COLLECTION_INNERCLASS::GetParticipant()); \ NS_LOG_ADDREF(this, count, #_class, sizeof(*this)); \ return count; #define NS_IMPL_CC_NATIVE_RELEASE_BODY(_class) \ MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release"); \ NS_ASSERT_OWNINGTHREAD(_class); \ nsrefcnt count = \ mRefCnt.decr(static_cast(this), \ _class::NS_CYCLE_COLLECTION_INNERCLASS::GetParticipant()); \ NS_LOG_RELEASE(this, count, #_class); \ return count; #define NS_IMPL_CYCLE_COLLECTING_NATIVE_ADDREF(_class) \ NS_METHOD_(MozExternalRefCountType) _class::AddRef(void) \ { \ NS_IMPL_CC_NATIVE_ADDREF_BODY(_class) \ } #define NS_IMPL_CYCLE_COLLECTING_NATIVE_RELEASE_WITH_LAST_RELEASE(_class, _last) \ NS_METHOD_(MozExternalRefCountType) _class::Release(void) \ { \ MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release"); \ NS_ASSERT_OWNINGTHREAD(_class); \ bool shouldDelete = false; \ nsrefcnt count = \ mRefCnt.decr(static_cast(this), \ _class::NS_CYCLE_COLLECTION_INNERCLASS::GetParticipant(), \ &shouldDelete); \ NS_LOG_RELEASE(this, count, #_class); \ if (count == 0) { \ mRefCnt.incr(static_cast(this), \ _class::NS_CYCLE_COLLECTION_INNERCLASS::GetParticipant()); \ _last; \ mRefCnt.decr(static_cast(this), \ _class::NS_CYCLE_COLLECTION_INNERCLASS::GetParticipant()); \ if (shouldDelete) { \ mRefCnt.stabilizeForDeletion(); \ DeleteCycleCollectable(); \ } \ } \ return count; \ } #define NS_IMPL_CYCLE_COLLECTING_NATIVE_RELEASE(_class) \ NS_METHOD_(MozExternalRefCountType) _class::Release(void) \ { \ NS_IMPL_CC_NATIVE_RELEASE_BODY(_class) \ } #define NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(_class) \ public: \ NS_METHOD_(MozExternalRefCountType) AddRef(void) { \ NS_IMPL_CC_NATIVE_ADDREF_BODY(_class) \ } \ NS_METHOD_(MozExternalRefCountType) Release(void) { \ NS_IMPL_CC_NATIVE_RELEASE_BODY(_class) \ } \ protected: \ nsCycleCollectingAutoRefCnt mRefCnt; \ NS_DECL_OWNINGTHREAD \ public: /////////////////////////////////////////////////////////////////////////////// /** * Use this macro to declare and implement the AddRef & Release methods for a * given non-XPCOM _class. * * @param _class The name of the class implementing the method * @param optional override Mark the AddRef & Release methods as overrides. */ #define NS_INLINE_DECL_REFCOUNTING(_class, ...) \ public: \ NS_METHOD_(MozExternalRefCountType) AddRef(void) __VA_ARGS__ { \ MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(_class) \ MOZ_ASSERT(int32_t(mRefCnt) >= 0, "illegal refcnt"); \ NS_ASSERT_OWNINGTHREAD(_class); \ ++mRefCnt; \ NS_LOG_ADDREF(this, mRefCnt, #_class, sizeof(*this)); \ return mRefCnt; \ } \ NS_METHOD_(MozExternalRefCountType) Release(void) __VA_ARGS__ { \ MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release"); \ NS_ASSERT_OWNINGTHREAD(_class); \ --mRefCnt; \ NS_LOG_RELEASE(this, mRefCnt, #_class); \ if (mRefCnt == 0) { \ NS_ASSERT_OWNINGTHREAD(_class); \ mRefCnt = 1; /* stabilize */ \ delete this; \ return 0; \ } \ return mRefCnt; \ } \ protected: \ nsAutoRefCnt mRefCnt; \ NS_DECL_OWNINGTHREAD \ public: /** * Use this macro to declare and implement the AddRef & Release methods for a * given non-XPCOM _class in a threadsafe manner. * * DOES NOT DO REFCOUNT STABILIZATION! * * @param _class The name of the class implementing the method */ #define NS_INLINE_DECL_THREADSAFE_REFCOUNTING(_class, ...) \ public: \ NS_METHOD_(MozExternalRefCountType) AddRef(void) __VA_ARGS__ { \ MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(_class) \ MOZ_ASSERT(int32_t(mRefCnt) >= 0, "illegal refcnt"); \ nsrefcnt count = ++mRefCnt; \ NS_LOG_ADDREF(this, count, #_class, sizeof(*this)); \ return (nsrefcnt) count; \ } \ NS_METHOD_(MozExternalRefCountType) Release(void) __VA_ARGS__ { \ MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release"); \ nsrefcnt count = --mRefCnt; \ NS_LOG_RELEASE(this, count, #_class); \ if (count == 0) { \ delete (this); \ return 0; \ } \ return count; \ } \ protected: \ ::mozilla::ThreadSafeAutoRefCnt mRefCnt; \ public: /** * Use this macro to implement the AddRef method for a given _class * @param _class The name of the class implementing the method */ #define NS_IMPL_ADDREF(_class) \ NS_IMETHODIMP_(MozExternalRefCountType) _class::AddRef(void) \ { \ MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(_class) \ MOZ_ASSERT(int32_t(mRefCnt) >= 0, "illegal refcnt"); \ if (!mRefCnt.isThreadSafe) \ NS_ASSERT_OWNINGTHREAD(_class); \ nsrefcnt count = ++mRefCnt; \ NS_LOG_ADDREF(this, count, #_class, sizeof(*this)); \ return count; \ } /** * Use this macro to implement the AddRef method for a given _class * implemented as a wholly owned aggregated object intended to implement * interface(s) for its owner * @param _class The name of the class implementing the method * @param _aggregator the owning/containing object */ #define NS_IMPL_ADDREF_USING_AGGREGATOR(_class, _aggregator) \ NS_IMETHODIMP_(MozExternalRefCountType) _class::AddRef(void) \ { \ MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(_class) \ NS_PRECONDITION(_aggregator, "null aggregator"); \ return (_aggregator)->AddRef(); \ } /** * Use this macro to implement the Release method for a given * _class. * @param _class The name of the class implementing the method * @param _destroy A statement that is executed when the object's * refcount drops to zero. * * For example, * * NS_IMPL_RELEASE_WITH_DESTROY(Foo, Destroy(this)) * * will cause * * Destroy(this); * * to be invoked when the object's refcount drops to zero. This * allows for arbitrary teardown activity to occur (e.g., deallocation * of object allocated with placement new). */ #define NS_IMPL_RELEASE_WITH_DESTROY(_class, _destroy) \ NS_IMETHODIMP_(MozExternalRefCountType) _class::Release(void) \ { \ MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release"); \ if (!mRefCnt.isThreadSafe) \ NS_ASSERT_OWNINGTHREAD(_class); \ nsrefcnt count = --mRefCnt; \ NS_LOG_RELEASE(this, count, #_class); \ if (count == 0) { \ if (!mRefCnt.isThreadSafe) \ NS_ASSERT_OWNINGTHREAD(_class); \ mRefCnt = 1; /* stabilize */ \ _destroy; \ return 0; \ } \ return count; \ } /** * Use this macro to implement the Release method for a given _class * @param _class The name of the class implementing the method * * A note on the 'stabilization' of the refcnt to one. At that point, * the object's refcount will have gone to zero. The object's * destructor may trigger code that attempts to QueryInterface() and * Release() 'this' again. Doing so will temporarily increment and * decrement the refcount. (Only a logic error would make one try to * keep a permanent hold on 'this'.) To prevent re-entering the * destructor, we make sure that no balanced refcounting can return * the refcount to |0|. */ #define NS_IMPL_RELEASE(_class) \ NS_IMPL_RELEASE_WITH_DESTROY(_class, delete (this)) /** * Use this macro to implement the Release method for a given _class * implemented as a wholly owned aggregated object intended to implement * interface(s) for its owner * @param _class The name of the class implementing the method * @param _aggregator the owning/containing object */ #define NS_IMPL_RELEASE_USING_AGGREGATOR(_class, _aggregator) \ NS_IMETHODIMP_(MozExternalRefCountType) _class::Release(void) \ { \ NS_PRECONDITION(_aggregator, "null aggregator"); \ return (_aggregator)->Release(); \ } #define NS_IMPL_CYCLE_COLLECTING_ADDREF(_class) \ NS_IMETHODIMP_(MozExternalRefCountType) _class::AddRef(void) \ { \ MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(_class) \ MOZ_ASSERT(int32_t(mRefCnt) >= 0, "illegal refcnt"); \ NS_ASSERT_OWNINGTHREAD(_class); \ nsISupports *base = NS_CYCLE_COLLECTION_CLASSNAME(_class)::Upcast(this); \ nsrefcnt count = mRefCnt.incr(base); \ NS_LOG_ADDREF(this, count, #_class, sizeof(*this)); \ return count; \ } #define NS_IMPL_CYCLE_COLLECTING_RELEASE_WITH_DESTROY(_class, _destroy) \ NS_IMETHODIMP_(MozExternalRefCountType) _class::Release(void) \ { \ MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release"); \ NS_ASSERT_OWNINGTHREAD(_class); \ nsISupports *base = NS_CYCLE_COLLECTION_CLASSNAME(_class)::Upcast(this); \ nsrefcnt count = mRefCnt.decr(base); \ NS_LOG_RELEASE(this, count, #_class); \ return count; \ } \ NS_IMETHODIMP_(void) _class::DeleteCycleCollectable(void) \ { \ _destroy; \ } #define NS_IMPL_CYCLE_COLLECTING_RELEASE(_class) \ NS_IMPL_CYCLE_COLLECTING_RELEASE_WITH_DESTROY(_class, delete (this)) // _LAST_RELEASE can be useful when certain resources should be released // as soon as we know the object will be deleted. #define NS_IMPL_CYCLE_COLLECTING_RELEASE_WITH_LAST_RELEASE(_class, _last) \ NS_IMETHODIMP_(MozExternalRefCountType) _class::Release(void) \ { \ MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release"); \ NS_ASSERT_OWNINGTHREAD(_class); \ bool shouldDelete = false; \ nsISupports *base = NS_CYCLE_COLLECTION_CLASSNAME(_class)::Upcast(this); \ nsrefcnt count = mRefCnt.decr(base, &shouldDelete); \ NS_LOG_RELEASE(this, count, #_class); \ if (count == 0) { \ mRefCnt.incr(base); \ _last; \ mRefCnt.decr(base); \ if (shouldDelete) { \ mRefCnt.stabilizeForDeletion(); \ DeleteCycleCollectable(); \ } \ } \ return count; \ } \ NS_IMETHODIMP_(void) _class::DeleteCycleCollectable(void) \ { \ delete this; \ } /////////////////////////////////////////////////////////////////////////////// /** * There are two ways of implementing QueryInterface, and we use both: * * Table-driven QueryInterface uses a static table of IID->offset mappings * and a shared helper function. Using it tends to reduce codesize and improve * runtime performance (due to processor cache hits). * * Macro-driven QueryInterface generates a QueryInterface function directly * using common macros. This is necessary if special QueryInterface features * are being used (such as tearoffs and conditional interfaces). * * These methods can be combined into a table-driven function call followed * by custom code for tearoffs and conditionals. */ struct QITableEntry { const nsIID* iid; // null indicates end of the QITableEntry array int32_t offset; }; nsresult NS_FASTCALL NS_TableDrivenQI(void* aThis, REFNSIID aIID, void** aInstancePtr, const QITableEntry* aEntries); /** * Implement table-driven queryinterface */ #define NS_INTERFACE_TABLE_HEAD(_class) \ NS_IMETHODIMP _class::QueryInterface(REFNSIID aIID, void** aInstancePtr) \ { \ NS_ASSERTION(aInstancePtr, \ "QueryInterface requires a non-NULL destination!"); \ nsresult rv = NS_ERROR_FAILURE; #define NS_INTERFACE_TABLE_BEGIN \ static const QITableEntry table[] = { #define NS_INTERFACE_TABLE_ENTRY(_class, _interface) \ { &NS_GET_IID(_interface), \ int32_t(reinterpret_cast( \ static_cast<_interface*>((_class*) 0x1000)) - \ reinterpret_cast((_class*) 0x1000)) \ }, #define NS_INTERFACE_TABLE_ENTRY_AMBIGUOUS(_class, _interface, _implClass) \ { &NS_GET_IID(_interface), \ int32_t(reinterpret_cast( \ static_cast<_interface*>( \ static_cast<_implClass*>( \ (_class*) 0x1000))) - \ reinterpret_cast((_class*) 0x1000)) \ }, /* * XXX: we want to use mozilla::ArrayLength (or equivalent, * MOZ_ARRAY_LENGTH) in this condition, but some versions of GCC don't * see that the static_assert condition is actually constant in those * cases, even with constexpr support (?). */ #define NS_INTERFACE_TABLE_END_WITH_PTR(_ptr) \ { nullptr, 0 } }; \ static_assert((sizeof(table)/sizeof(table[0])) > 1, "need at least 1 interface"); \ rv = NS_TableDrivenQI(static_cast(_ptr), \ aIID, aInstancePtr, table); #define NS_INTERFACE_TABLE_END \ NS_INTERFACE_TABLE_END_WITH_PTR(this) #define NS_INTERFACE_TABLE_TAIL \ return rv; \ } #define NS_INTERFACE_TABLE_TAIL_INHERITING(_baseclass) \ if (NS_SUCCEEDED(rv)) \ return rv; \ return _baseclass::QueryInterface(aIID, aInstancePtr); \ } #define NS_INTERFACE_TABLE_TAIL_USING_AGGREGATOR(_aggregator) \ if (NS_SUCCEEDED(rv)) \ return rv; \ NS_ASSERTION(_aggregator, "null aggregator"); \ return _aggregator->QueryInterface(aIID, aInstancePtr) \ } /** * This implements query interface with two assumptions: First, the * class in question implements nsISupports and its own interface and * nothing else. Second, the implementation of the class's primary * inheritance chain leads to its own interface. * * @param _class The name of the class implementing the method * @param _classiiddef The name of the #define symbol that defines the IID * for the class (e.g. NS_ISUPPORTS_IID) */ #define NS_IMPL_QUERY_HEAD(_class) \ NS_IMETHODIMP _class::QueryInterface(REFNSIID aIID, void** aInstancePtr) \ { \ NS_ASSERTION(aInstancePtr, \ "QueryInterface requires a non-NULL destination!"); \ nsISupports* foundInterface; #define NS_IMPL_QUERY_BODY(_interface) \ if ( aIID.Equals(NS_GET_IID(_interface)) ) \ foundInterface = static_cast<_interface*>(this); \ else #define NS_IMPL_QUERY_BODY_CONDITIONAL(_interface, condition) \ if ( (condition) && aIID.Equals(NS_GET_IID(_interface))) \ foundInterface = static_cast<_interface*>(this); \ else #define NS_IMPL_QUERY_BODY_AMBIGUOUS(_interface, _implClass) \ if ( aIID.Equals(NS_GET_IID(_interface)) ) \ foundInterface = static_cast<_interface*>( \ static_cast<_implClass*>(this)); \ else #define NS_IMPL_QUERY_BODY_AGGREGATED(_interface, _aggregate) \ if ( aIID.Equals(NS_GET_IID(_interface)) ) \ foundInterface = static_cast<_interface*>(_aggregate); \ else #define NS_IMPL_QUERY_TAIL_GUTS \ foundInterface = 0; \ nsresult status; \ if ( !foundInterface ) \ { \ /* nsISupports should be handled by this point. If not, fail. */ \ MOZ_ASSERT(!aIID.Equals(NS_GET_IID(nsISupports))); \ status = NS_NOINTERFACE; \ } \ else \ { \ NS_ADDREF(foundInterface); \ status = NS_OK; \ } \ *aInstancePtr = foundInterface; \ return status; \ } #define NS_IMPL_QUERY_TAIL_INHERITING(_baseclass) \ foundInterface = 0; \ nsresult status; \ if ( !foundInterface ) \ status = _baseclass::QueryInterface(aIID, (void**)&foundInterface); \ else \ { \ NS_ADDREF(foundInterface); \ status = NS_OK; \ } \ *aInstancePtr = foundInterface; \ return status; \ } #define NS_IMPL_QUERY_TAIL_USING_AGGREGATOR(_aggregator) \ foundInterface = 0; \ nsresult status; \ if ( !foundInterface ) { \ NS_ASSERTION(_aggregator, "null aggregator"); \ status = _aggregator->QueryInterface(aIID, (void**)&foundInterface); \ } else \ { \ NS_ADDREF(foundInterface); \ status = NS_OK; \ } \ *aInstancePtr = foundInterface; \ return status; \ } #define NS_IMPL_QUERY_TAIL(_supports_interface) \ NS_IMPL_QUERY_BODY_AMBIGUOUS(nsISupports, _supports_interface) \ NS_IMPL_QUERY_TAIL_GUTS /* This is the new scheme. Using this notation now will allow us to switch to a table driven mechanism when it's ready. Note the difference between this and the (currently) underlying NS_IMPL_QUERY_INTERFACE mechanism. You must explicitly mention |nsISupports| when using the interface maps. */ #define NS_INTERFACE_MAP_BEGIN(_implClass) NS_IMPL_QUERY_HEAD(_implClass) #define NS_INTERFACE_MAP_ENTRY(_interface) NS_IMPL_QUERY_BODY(_interface) #define NS_INTERFACE_MAP_ENTRY_CONDITIONAL(_interface, condition) \ NS_IMPL_QUERY_BODY_CONDITIONAL(_interface, condition) #define NS_INTERFACE_MAP_ENTRY_AGGREGATED(_interface,_aggregate) \ NS_IMPL_QUERY_BODY_AGGREGATED(_interface,_aggregate) #define NS_INTERFACE_MAP_END NS_IMPL_QUERY_TAIL_GUTS #define NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(_interface, _implClass) \ NS_IMPL_QUERY_BODY_AMBIGUOUS(_interface, _implClass) #define NS_INTERFACE_MAP_END_INHERITING(_baseClass) \ NS_IMPL_QUERY_TAIL_INHERITING(_baseClass) #define NS_INTERFACE_MAP_END_AGGREGATED(_aggregator) \ NS_IMPL_QUERY_TAIL_USING_AGGREGATOR(_aggregator) #define NS_INTERFACE_TABLE0(_class) \ NS_INTERFACE_TABLE_BEGIN \ NS_INTERFACE_TABLE_ENTRY(_class, nsISupports) \ NS_INTERFACE_TABLE_END #define NS_INTERFACE_TABLE(aClass, ...) \ MOZ_STATIC_ASSERT_VALID_ARG_COUNT(__VA_ARGS__); \ NS_INTERFACE_TABLE_BEGIN \ MOZ_FOR_EACH(NS_INTERFACE_TABLE_ENTRY, (aClass,), (__VA_ARGS__)) \ NS_INTERFACE_TABLE_ENTRY_AMBIGUOUS(aClass, nsISupports, \ MOZ_ARG_1(__VA_ARGS__)) \ NS_INTERFACE_TABLE_END #define NS_IMPL_QUERY_INTERFACE0(_class) \ NS_INTERFACE_TABLE_HEAD(_class) \ NS_INTERFACE_TABLE0(_class) \ NS_INTERFACE_TABLE_TAIL #define NS_IMPL_QUERY_INTERFACE(aClass, ...) \ NS_INTERFACE_TABLE_HEAD(aClass) \ NS_INTERFACE_TABLE(aClass, __VA_ARGS__) \ NS_INTERFACE_TABLE_TAIL /** * Declare that you're going to inherit from something that already * implements nsISupports, but also implements an additional interface, thus * causing an ambiguity. In this case you don't need another mRefCnt, you * just need to forward the definitions to the appropriate superclass. E.g. * * class Bar : public Foo, public nsIBar { // both provide nsISupports * public: * NS_DECL_ISUPPORTS_INHERITED * ...other nsIBar and Bar methods... * }; */ #define NS_DECL_ISUPPORTS_INHERITED \ public: \ NS_IMETHOD QueryInterface(REFNSIID aIID, \ void** aInstancePtr) override; \ NS_IMETHOD_(MozExternalRefCountType) AddRef(void) override; \ NS_IMETHOD_(MozExternalRefCountType) Release(void) override; \ /** * These macros can be used in conjunction with NS_DECL_ISUPPORTS_INHERITED * to implement the nsISupports methods, forwarding the invocations to a * superclass that already implements nsISupports. * * Note that I didn't make these inlined because they're virtual methods. */ #define NS_IMPL_ADDREF_INHERITED(Class, Super) \ NS_IMETHODIMP_(MozExternalRefCountType) Class::AddRef(void) \ { \ MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(Class) \ nsrefcnt r = Super::AddRef(); \ NS_LOG_ADDREF(this, r, #Class, sizeof(*this)); \ return r; \ } #define NS_IMPL_RELEASE_INHERITED(Class, Super) \ NS_IMETHODIMP_(MozExternalRefCountType) Class::Release(void) \ { \ nsrefcnt r = Super::Release(); \ NS_LOG_RELEASE(this, r, #Class); \ return r; \ } /** * As above but not logging the addref/release; needed if the base * class might be aggregated. */ #define NS_IMPL_NONLOGGING_ADDREF_INHERITED(Class, Super) \ NS_IMETHODIMP_(MozExternalRefCountType) Class::AddRef(void) \ { \ MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(Class) \ return Super::AddRef(); \ } #define NS_IMPL_NONLOGGING_RELEASE_INHERITED(Class, Super) \ NS_IMETHODIMP_(MozExternalRefCountType) Class::Release(void) \ { \ return Super::Release(); \ } #define NS_INTERFACE_TABLE_INHERITED0(Class) /* Nothing to do here */ #define NS_INTERFACE_TABLE_INHERITED(aClass, ...) \ MOZ_STATIC_ASSERT_VALID_ARG_COUNT(__VA_ARGS__); \ NS_INTERFACE_TABLE_BEGIN \ MOZ_FOR_EACH(NS_INTERFACE_TABLE_ENTRY, (aClass,), (__VA_ARGS__)) \ NS_INTERFACE_TABLE_END #define NS_IMPL_QUERY_INTERFACE_INHERITED0(aClass, aSuper) \ NS_INTERFACE_TABLE_HEAD(aClass) \ NS_INTERFACE_TABLE_INHERITED0(aClass) \ NS_INTERFACE_TABLE_TAIL_INHERITING(aSuper) #define NS_IMPL_QUERY_INTERFACE_INHERITED(aClass, aSuper, ...) \ NS_INTERFACE_TABLE_HEAD(aClass) \ NS_INTERFACE_TABLE_INHERITED(aClass, __VA_ARGS__) \ NS_INTERFACE_TABLE_TAIL_INHERITING(aSuper) /** * Convenience macros for implementing all nsISupports methods for * a simple class. * @param _class The name of the class implementing the method * @param _classiiddef The name of the #define symbol that defines the IID * for the class (e.g. NS_ISUPPORTS_IID) */ #define NS_IMPL_ISUPPORTS0(_class) \ NS_IMPL_ADDREF(_class) \ NS_IMPL_RELEASE(_class) \ NS_IMPL_QUERY_INTERFACE0(_class) #define NS_IMPL_ISUPPORTS(aClass, ...) \ NS_IMPL_ADDREF(aClass) \ NS_IMPL_RELEASE(aClass) \ NS_IMPL_QUERY_INTERFACE(aClass, __VA_ARGS__) #define NS_IMPL_ISUPPORTS_INHERITED0(aClass, aSuper) \ NS_IMPL_QUERY_INTERFACE_INHERITED0(aClass, aSuper) \ NS_IMPL_ADDREF_INHERITED(aClass, aSuper) \ NS_IMPL_RELEASE_INHERITED(aClass, aSuper) \ #define NS_IMPL_ISUPPORTS_INHERITED(aClass, aSuper, ...) \ NS_IMPL_QUERY_INTERFACE_INHERITED(aClass, aSuper, __VA_ARGS__) \ NS_IMPL_ADDREF_INHERITED(aClass, aSuper) \ NS_IMPL_RELEASE_INHERITED(aClass, aSuper) /* * Macro to glue together a QI that starts with an interface table * and segues into an interface map (e.g. it uses singleton classinfo * or tearoffs). */ #define NS_INTERFACE_TABLE_TO_MAP_SEGUE \ if (rv == NS_OK) return rv; \ nsISupports* foundInterface; /////////////////////////////////////////////////////////////////////////////// /** * * Threadsafe implementations of the ISupports convenience macros. * * @note These are not available when linking against the standalone glue, * because the implementation requires PR_ symbols. */ #define NS_INTERFACE_MAP_END_THREADSAFE NS_IMPL_QUERY_TAIL_GUTS /** * Macro to generate nsIClassInfo methods for classes which do not have * corresponding nsIFactory implementations. */ #define NS_IMPL_THREADSAFE_CI(_class) \ NS_IMETHODIMP \ _class::GetInterfaces(uint32_t* _count, nsIID*** _array) \ { \ return NS_CI_INTERFACE_GETTER_NAME(_class)(_count, _array); \ } \ \ NS_IMETHODIMP \ _class::GetScriptableHelper(nsIXPCScriptable** _retval) \ { \ *_retval = nullptr; \ return NS_OK; \ } \ \ NS_IMETHODIMP \ _class::GetContractID(char** _contractID) \ { \ *_contractID = nullptr; \ return NS_OK; \ } \ \ NS_IMETHODIMP \ _class::GetClassDescription(char** _classDescription) \ { \ *_classDescription = nullptr; \ return NS_OK; \ } \ \ NS_IMETHODIMP \ _class::GetClassID(nsCID** _classID) \ { \ *_classID = nullptr; \ return NS_OK; \ } \ \ NS_IMETHODIMP \ _class::GetFlags(uint32_t* _flags) \ { \ *_flags = nsIClassInfo::THREADSAFE; \ return NS_OK; \ } \ \ NS_IMETHODIMP \ _class::GetClassIDNoAlloc(nsCID* _classIDNoAlloc) \ { \ return NS_ERROR_NOT_AVAILABLE; \ } #endif